Contrails
The goal of the Contrails project is to help preserve and disseminate the technical record of 20th century aerospace research, highlighting in particular the research endeavors of the Illinois Tech community.

Use of Dichromatic Earpiece Densitometry for Determination of Cardiac Output

Report Number: AMRL TR 64-134
Author: Reed, John H., Jr.
Author: Wood, Earl H.
Corporate Author: The Mayo Clinic and Mayo Graduate School of Medicine
Laboratory: Biophysics Laboratory
Date of Publication: 1964-12
Pages: 20
Contract: AF 33(657)-8899
Project: 7222
AD Number: AD0613335

Abstract:
Dye-dilution curves were recorded simultaneously by a monochromatic earpiece densitometer, a dichromatic earpiece densitometer and a cuvette densitometer through which blood was sampled continuously from a radial artery. Comparison of cardiac output values were made using the direct coupled arterial cuvette as a standard in nine healthy subjects during three periods of rest and during two periods of pedalling a bicycle ergometer at different levels of work output. Data are also included from similar studies carried out in five cardiac patients in whom no great vessel or intracardiac shunts could be demonstrated. The results showed a high degree of variability for the monochromatic earpiece densitometer values (standard deviation of differences: =31%) because of baseline variations due to changing conditions in the ear. The dichromatic earpiece densitometer which compensates for dynamic changes in the ear showed satisfactory comparison with arterial cuvette densitometer (standard deviation of differences: =14%). The dichromatic earpiece densitometer showed a linear relationship between its calibration factor for dye (centimeters deflection/milligrams dye/liter of blood) and the relative blood content of the ear. A dichromatic ear densitometer appears feasible for estimating cardiac output where use of more direct methods is precluded.


Provenance:
RAF Centre of Aviation Medicine
Download this report

(PDF, 0.64 MB, 20 pages)

Other options for obtaining this report

Via the Defense Technical Information Center (DTIC):
A record for this report, and possibly a full-image download of the report, exists at DTIC

Via National Technical Information Service:
This report may have been digitized and made freely available for public download, or made publicly available for purchase by the National Technical Information Service through their online database, the National Technical Reports Library

Indications of Public Availability
No digital image of an index entry indicating public availability is currently available
There has been no verification of an indication of public availability from an inside cover statement